A checkweigher is tested at start of shift, at product changeover and after repair using a reference weight or pack, and the result is recorded. Periodic calibration with certified weights confirms scale accuracy and automatic rejection.
Like a metal detector, a checkweigher must be able to show at any time that it is working properly. An auditor does not trust the number on the display; he asks for test records and a calibration certificate.
In the daily test a reference pack of known weight (or a certified weight inside a pack) is passed through. Expected results: the display is close to the true weight, a pack inside the limits is accepted, and an underweight or overweight pack (a weight removed or added) is rejected. Run the test with real product on the current profile, not on an empty belt.
The interval is set by site quality procedure, customer or standard. Testing is normally carried out:
Calibration is a periodic confirmation of the machine's scale accuracy against certified reference weights, with a check of zero (tare), repeatability and reject function, carried out by a qualified technician with a certificate issued. The reference weights themselves must hold a valid certificate.
The test form carries date and time, shift, product, reference weight, pass/fail result and signature. If a test fails, product made since the last passed test is quarantined and re-weighed, the cause is investigated and production resumes only after a successful test. For metal-detector practice on the same lines see choosing an industrial metal detector.
Regular tests, certified weights and records build trust in a checkweigher. If your site's test procedure is not yet written, we can help define reference weights and the log sheet.
Share your production line's specs with us and we'll recommend the right model.
The interval is set by the quality procedure or customer; commonly at start of shift, at product changeover and after repair or washdown.
A reference pack of known weight or a certified weight, used to confirm acceptance of a good pack and rejection of an out-of-range pack.
The daily test confirms momentary function; calibration checks scale accuracy against certified weights and issues a certificate.
Quarantine and re-weigh product since the last passed test, fix the cause, repeat the test and record every step.
